Foliar applied herbicidal compositions containing a silicone glycolsilicone alkane terpolymer adjuvant

ABSTRACT

There is disclosed a herbicidal composition in which a foliar-applied herbicide is activated by the inclusion of a silicone glycol-silicone alkane terpolymer adjuvant. The composition provides enhanced phytotoxicity in the control of narrowleaf weeds, particularly Barnyardgrass, Quackgrass and Johnsongrass, and often also shows an improved degree of rainfastness relative to similar herbicidal compositions employing prior art silicone glycol adjuvants.

This is a Continuation-in-Part of Serial No. 07/365,628, filed on June13, 1989 now abandoned.

This invention relates to foliar-applied herbicide formulations. Moreparticularly, the present invention relates to compositions offoliar-applied herbicides which are activated by the inclusion ofcertain silicone glycol-silicone alkane terpolymer adjuvants.

BACKGROUND OF THE INVENTION

It is well recognized in the art that the full efficacy of a givenorganic herbicide is not generally attained without the inclusion ofvarious adjuvants, an adjuvant being broadly defined as any substancewhich enhances the effectiveness of the herbicide. Thus, for example,through proper formulation with an activity-increasing adjuvant, thecontrol of a particular plant species by an herbicide can be greatlyaugmented. Such an activity-increasing adjuvant does not generally havebiological activity on its own but only brings out the activity of theherbicide.

An example of the aforementioned activity-increasing adjuvants is theclass of surfactants known as silicone glycols. These liquids have beenshown to enhance the efficacy of various herbicides. L. L. Jansen (WeedScience, v. 21, pages 130-135, Mar. 1973) examined the effect of addingvarious silicone glycol adjuvants to different herbicides and reportedthat these adjuvants were superior to a standard organic surfactant ineight plant species. In this study, cationic amino silicone surfactantswere also evaluated, but found to be less effective than the organicmaterial. In any event, no specific structures of the silicone compoundswere provided in this paper.

Great Britain Pat. No. 1,255,249 to Dow Corning Corporation, publishedDec. 1, 1971, again discloses herbicide compositions employing siliconeglycol copolymers. Here, general utility of a large number of adjuvantsis professed, as exemplified by two generic silicone glycol formulaswhich embrace structures having both diorganosiloxane units andalkyl-glycol siloxane units. There is also provided a wide-ranging listof suitable herbicides. This reference, however, provides littledirection to those skilled in the art as to which particular siliconeglycol structures are to be advantageously combined with specificherbicides, save for two examples employing a triazine herbicide inconjunction with an adjuvant having 1.8 siloxy units and bearing aglycol chain having 12 ethylene oxide units.

In addition to the herbicidal enhancement provided by theactivity-increasing adjuvants discussed above, it is often importantthat herbicide formulations retain a significant degree of activity whenplants treated therewith are exposed to rain shortly after application,this being a definition of the degree of "rainfastness." This isparticularly critical for water-soluble foliar-applied herbicides, suchas glyphosate salts, which may be washed away by rainfall occurringwithin about six hours of application. Typically, this problem iscurrently addressed by inclusion of another class of adjuvants in theherbicide formulation, namely sticking agents (see, for example, page 6of Adjuvants for Herbicides, Weed Science Society of America, Champaign,IL, 1982). The main function of these materials, as the appelationimplies, is to impart an increased measure of adhesion of the herbicidecomposition to plant foliage and thus reduce premature washing awayshould precipitation occur after the plants are sprayed. The stickingagents are usually polymeric compounds which are generally water-solubleand tacky in nature.

Neither Jansen nor British Pat. No. 1,255,249 addresses the issue ofrainfastness nor does any reference suggest to those of ordinary skillin the art the use of applicants' particular silicone glycol-siliconealkane terpolymers to provide enhanced activity in conjunction withparticular herbicides.

SUMMARY OF THE INVENTION

It has now been found that the efficacy of a foliar-applied herbicidecan be synergistically increased by the inclusion of a siliconeglycol-silicone alkane terpolymer in a herbicidally effectivecomposition, "herbicidally effective" meaning that the compositionprovides the desired kill control of the particular weed in question.Moreover, this combination can provide increased rainfastness in thevery same formulation without the need for an additional sticking agent.

The present invention therefore relates to a composition comprising:

(I) a foliar-applied herbicide; and

(II) from about 0.1 to about 10 parts by weight, for each part by weightof said herbicide (I), of a silicone glycol-silicone alkane terpolymeradjuvant having the average formula selected from the group consistingof ##STR1## wherein Me denotes a methyl radical, A is a linear orbranched alkyl radical having 6 to 24 carbon atoms, G is a glycol moietyhaving the formula --R'(OCH₂ CH₂)_(m) OZ, in which R' is a divalentalkylene group having 2 to 6 carbon atoms, Z is selected from the groupconsisting of hydrogen, an alkyl radical having 1 to 3 carbon atoms andan acyl group having 2 to 4 carbon atoms and m is 12 to 32, x is 0.01 to3, y is 0.1 to 1.25 and z is 0.75 to 1.9, with the proviso that when theweight fraction of --OCH₂ CH₂ -- groups of said glycol moiety G is lessthan 0.7 said alkyl radical A contains from 6 to 12 carbon atoms andwhen the weight fraction of --OCH₂ CH₂ -- groups of said glycol moiety Gis more than 0.8 said alkyl radical A contains from 8 to 24 carbonatoms.

The present invention further relates to a method for inhibiting thegrowth of narrowleaf annual and perennial weeds, particularlyBarnyardgrass, Rhizone Johnsongrass and Rhizome Quackgrass, comprisingcontacting at least part of the weed with the aforementioned herbicidalcomposition.

DETAILED DESCRIPTION OF THE INVENTION

The herbicidal composition of the present invention is a homogeneousmixture comprising (I) a foliar-applied herbicide and (II) a siliconeglycol-silicone alkane terpolymer adjuvant.

The foliar-applied herbicide (I) of the present invention is selectedfrom those herbicides well known in the art to be effective when appliedafter the emergence of a plant.

Herbicides which are useful in this invention include triazines, ureas,carbamates, acetamides, uracils, acetic acid or phenol derivatives,triazoles, benzoic acids, nitriles, biphenyl ethers and the like suchas:

Heterocyclic nitrogen/sulfur derivatives including2-chloro-4-ethylamino-6-isopropylamino-s-triazine, 2-chloro-4,6-bis(isopropylamino)-s-triazine; 6-bis(isopropylamino)-s-triazine;2-chloro-4,6-bis(ethylamine)-s-triazine;3-isopropyl-1H-2,1,3-benzothiadiazin-4-(3H)-one 2,2-dioxide,3-amino-1,2,4-triazole; 5-bromo-3-isopropyl-6-methyluracil;2-(4-isopropyl-4-methyl-5-oxo-2-imdazolin-2-yl-)3-quinolinecarboxylicacid; isopropylamine salt of2-(4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid, methyl6-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-m-toluate; and methyl2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-p-toluate; and furtherincluding acids/esters/alcohols such as (2,2-dichloropropionic acid;2-methyl-4-chloropheno xyacetic acid, 2,4-dichlorophenoxyacetic acid,methyl-2-[4-(2,4-dichlorophenoxy)phenoxy]propionate,3-amino-2,5-dichlorobenzoic acid, 2-methoxy-3,6-dichlorobenzoic acid,2,3,6-trichlorophenylacetic acid, N-1-naphthylphthalamic acid, sodium5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoate,4,6-dinitro-o-sec-butylphenol, butyl2-[-[(trifluoromethyl)-2-pyridinyl)oxy]-phenoxy]-propanoate; andcyclohexanediones such as sethoxydium and garlon and ethers such as2,4-dichlorophenyl-4-nitrophenyl ether,2-chloro-trifuluorop-tolyl-3-ethoxy-4-nitrodiphenyl ether,5-(2-chloro-4-trifluoromethylphenoxy)-N-methylsulfonyl 2-nitrobenzamide,1'-(carboethoxy) ethyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoate and other diphenylethers and othermiscellaneous herbicides such as 2,6-dichlorobenzonitrile, monosodiumacid methanearsonate, disodium methanearsonate,2-(2-chlorophenyl)methyl-4,4-dimethyl-3-isoxazolidinone.

One preferred foliar-applied herbicide is N-phosphonomethylglycine(glyphosate) or an agriculturally acceptable salt thereof. Theisopropylamine salt of this compound is marketed under the trade nameROUNDUP (Monsanto Agricultural Products Co., St. Louis, Mo.), and isparticularly preferred.

Other preferred herbicides of the present invention may be selected fromsulfonylurea herbicides, such as those marketed by Du Pont (Wilmington,Del.) under the trade names ACCENT, HARMONY, CLASSIC, PINNACLE, EXPRESS,GLEAN, ALLY and FINESS. A particularly preferred herbicide of this classis3-[4,6-bis(difluoromethoxy)-pyrimidin-2yl]-1-(2-methoxycarbonylphenylsulfonyl)-urea(common name: Primisulfuron). This material is marketed under the tradename BEACON (Ciba-Geigy Agricultural Division, Greensboro, N.C.).

The silicone glycol-silicone alkane terpolymer (II) of the presentinvention has the average structure selected from the group consistingof ##STR2## wherein Me hereinafter denotes a methyl radical, A is alinear or branched alkyl radical having 6 to 24 carbon atoms and G is aglycol moiety having the formula --R'(OCH₂ CH₂)_(m) OZ, in which R' is adivalent alkylene group having 2 to 6 carbon atoms, Z is selected fromthe group consisting of hydrogen, an alkyl radical having 1 to 3 carbonatoms and an acyl group having 2 to 4 carbon atoms. In the aboveformulas, m is 12 to 32, x is 0.01 to 3, y is 0.1 to 1.25 and z is 0.75to 1.9.

In addition to the above stated restrictions, it has been found thatcomponent (II) of the present invention must further be limited suchthat the number of carbon atoms of alkyl radical A is 6 to 12 when thecalculated hydrophilic-lipophilic balance (HLB) of the terpolymer isless than 14 and the number of carbon atoms of A is 8 to 24 when thecalculated HLB is greater than 16. The calculated HLB value is definedherein as the weight percent of ethylene oxide units (i.e., --OCH₂ CH₂-- units) in the terpolymer divided by 5. Thus, in order to be withinthe scope of the present invention, the number of carbon atoms of alkylradical A is 6 to 12 when the weight fraction of ethylene oxide units isless than 0.7 and the number of carbon atoms of A is 8 to 24 when theweight fraction of ethylene oxide units is greater than 0.8.

A particularly preferred component (II) of the present invention has theaverage formula ##STR3##

The silicone glycol-silicone alkane terpolymers described above may beprepared by methods well known in the art. Briefly, for example, thecorresponding allyl-terminated glycol and alpha-alkene are coupled to anSiH-functional siloxane having the average structure ##STR4## Couplingis accomplished in the presence of a platinum catalyst at temperaturesin the range of about 20° C. to about 150° C., the reaction preferablybeing carried out at about 105° C. using an effective amount of asolvent such as toluene or isopropanol. The skilled artisan willrecognize that, in such hydrosilylation reactions, a fraction of theallyl-terminated glycol and the alpha-alkene is not converted and willremain as an impurity in the final product terpolymer. The herbicidalcompositions may contain such impurities and still be within the scopeof the present invention.

In addition to the aforementioned components, the compositions of thepresent invention may also contain other herbicide adjuvants commonlyemployed in the art.

The phytotoxicant compositions of this invention, preferably contain (inaddition to the herbicide active and silicone) an inert adjuvant orconditioning agent and one or more surface-active agents in amountssufficient to render a given composition readily dispersible in water orin oil. The incorporation of a surface active agent into thecompositions of this invention greatly enhances their efficacy. By theterm surface active agent, it is understood that wetting agents,dispersing agents, suspending agents and emulsifying agents are includedtherein. Anionic, cationic and nonionic agents can be employed withequal facility.

Preferred wetting agents are alkyl benezene and alkyl naphthalenesulfonates, sulfated fatty alcohols, amines or acid amides, long chainacid esters of sodium isothionate, esters of sodium sulfosuccinate,sulfated or sulfonated fatty acid esters, petroleum sulfonates,sulfonated vegetable oils, ditertiary acetylenic glycols,polyoxyethylene derivatives of alkyl phenols (particularlyisooctylphenol and nonylphenol), polyoxyethylene derivatives of fattyacid esters of hexito anyhydrides (sorbitan) and silicone glycols.Preferred dispersants are methylcellulose, polyvinylalcohol, sodiumlignin sulfonates, polymeric alky naphthalene sulfonates, sodiumnaphthalene sulfonate, polymethylene bisnahpthalenesulfonates and sodiumN-methyl-N-long chain acid laurates.

Suitable surfactants (adjuvants) are disclosed in U.S. Pat. No.3,799,758 and 4,405,531, both of which are incorporated herein in theirentirety by reference. Examples of other adjuvants include crop oilconcentrate, ORTHO X-77 spreader, drift control agents, such asLO-DRIFT, defoaming agents, such as D-FOAMER, compatibility agents, suchas E-Z MIX, and other adjuvants well known in the herbicide art.

In order to prepare the compositions of the present invention, fromabout 0.1 to about 10 parts by weight of the silicone glycol-siliconealkane terpolymer (II) is thoroughly mixed with each part by weight ofherbicide (I). Preferably, from 0.5 to 4 parts by weight of (II) areemployed for each part of the pesticide (I). For a given herbicide, theskilled artisan will readily arrive at a herbicidal composition havingthe optimum ratio of the ingredients by routine experimentation.

The above herbicidal composition may then be dispersed in water andsprayed onto plants according to the method of the present invention,described infra. Alternatively, the silicone glycol-silicone alkaneterpolymer adjuvant (II) may be added directly to a water solution ordispersion of herbicide (I).

The present invention also relates to a method for inhibiting the growthof narrow-leaf weeds, particularly the species Echinochloa crus-galli,hereinafter referred to by its common name of "Barnyardgrass," Agropyronrepens, hereinafter referred to by its common name of "Quackgrass" andSorghum halepense, hereinafter referred to by its common name"Johnsongrass." This method comprises contacting at least part of theweed with the above described herbicidal composition. This composition,usually in water dispersion form, is applied to the foliage of the weedby any of the methods commonly practiced in the art, preferably byspraying. The composition may be either a package mix or a tank mix. Theamount of the dispersion, and the herbicide contained therein, to beapplied to the weed may be varied to a great extent, the optima beingdetermined by such factors as soil conditions, weather conditions andthe type of crops or other plants growing alongside the weed. Generally,however, the effective application rate is about 0.5 to 10 pounds peracre of herbicide formulation. The skilled artisan is directed to U.S.Pat. Nos. 3,799,758 and 4,405,531, hereby incorporated by reference, forfurther suggestions as to appropriate application rates forN-phosphonomethylglycine based herbicides.

When the compositions of the present invention are used according to theabove described method, there is observed a statistically significantimprovement in the efficacy and/or rainfastness of the herbicidalcompositions relative to compositions employing prior art siliconeglycol adjuvants or only the unmodified herbicide. There is provided adistinct advantage by the instant compositions in that they permit theuse of lower herbicide levels to attain a similar degree of injury to aweed, this advantage often being maximized when there is a reasonablelikelihood of precipitation after applying the herbicide. Such areduction in herbicide levels generally results in reduced injury toadjacent cash crops and is considered highly desirable.

EXAMPLES

The following examples are presented to further illustrate thecompositions of this invention, but are not to be construed as limitingthe invention, which is delineated in the appended claims. All parts andpercentages in the examples are on a weight basis unless indicated tothe contrary.

EXAMPLES 1-10

A silicone glycol-silicone alkane terpolymer adjuvant of the presentinvention was prepared as follows. A three neck 1 liter flask, equippedwith nitrogen inlet/thermometer, claisen head with additionfunnel/condenser and mechanical air driven stirrer was charged with50.37 g (0.17 mole) of an SiH-functional siloxane having the averageformula ##STR5## 24.2 g (0.14 mole) of alpha-dodecene, 398.2 g (0.32mole) of an allyl-functional glycol having the formula CH₂ ═CHCH₂ (OCH₂CH₂)₂₄ OC(O)CH₃ and 0.2 g of sodium acetate. Dissolved air was removedfrom the mixture under vacuum, the flask was purged with nitrogen gasand the contents heated to 140° C. The stirred mixture was thencatalyzed with 10 ppm of chloroplatinic acid (as a 1% solution inisopropyl alcohol). The exothermic reaction brought the temperature ofthe mixture to 155° C. The mixture was held at a temperature of 150° C.for 2 hours, after which all of the initial SiH functionality hadreacted, as determined by IR analysis. The mixture was cooled to 50° C.and 0.5 wt % Nucap 200, 0.5 wt % Celite 545 (filtration aids) and 150 gof isopropanol were added. This mixture was stirred for one hour,pressure filtered and the isopropanol solvent vacuum stripped off toprovide 423.5 g (90% yield) of a final product having the calculatedaverage formula ##STR6## wherein Me hereinafter denotes a methylradical. This product is designated as FLUID A in Table 1.

A similar procedure was employed to prepare other siliconeglycol-silicone alkane terpolymers (FLUIDS B-G) and comparative siliconeglycols (FLUIDS J-K), also shown in Table 1. These fluids had theaverage formula ##STR7## wherein A is a normal alkyl radical having ncarbon atoms, G is an acetoxy terminated glycol moiety having theformula --CH₂ CH₂ CH₂ (OCH₂ CH₂)_(m) OC(O)CH₃, the values of m, n, x, yand z for the various terpolymers being given in Table 1, below.

                  TABLE 1                                                         ______________________________________                                        FLUID    n         m     x       y    z                                       ______________________________________                                        A        12        24    0       0.64 1.36                                    B        12        24    8.5     1.00 4.50                                    C        12        24    2.00    1.50 2.50                                    D        12         4    8.50    0.50 5.00                                    E        12         4    2.00    0.50 3.50                                    F        12         4    0       0.25 1.75                                    G        12        12    19.00   2.00 9.00                                    H        12        12    0       0.64 1.36                                    I         8        12    0       0.73 1.27                                    J        --         7    0       0    1.00                                    K*       --         4    0       0    1.00                                    L-77**                                                                        ______________________________________                                         ##STR8##                                                                      **SILWET L77 (Union Carbide Corp., Danbury, CT)                          

Comparative silicone glycol adjuvants used in the following evaluationsof herbicidal activity included:

FLUID J, described in Table 1.

FLUID K, also described in Table 1.

SILWET L-77 (Union Carbide Corp., Danbury, CT) is described as asilicone glycol surfactant for use in agriculture.

Test Protocol

The following weed species were used as indicator weeds:

    ______________________________________                                        Common Name         Scientific Name                                           ______________________________________                                        Rhizome Quakgrass   Agropyron repens                                          Rhizome Johnsongrass                                                                              Sorghum halepense                                         Barnyardgrass       Echinochloa crus-galli                                    Velvetleaf (a broadleaf)                                                                          Abutilon theophrasti                                      ______________________________________                                    

The narrowleaf and broadleaf test weeds were seeded separately intoplastic pots 4 inches in diameter and 3 inches deep with drainage holeson the bottom. The pots contained Dupo silt loam soil obtained from theSt. Charles Research Farm of Monsanto Company located in St. Charles,Mo. Prior to use, the soil was steam sterilized at a temperature of 180°F. The soil used was mixed with a slow release 14-14-14 fertilizer.

Barnyard grass and velvetleaf were started from seeds while rhizomejohnsongrass and rhizome quackgrass plants were grown from rhizomepieces. In all cases, sufficient seeds or stock propagules were plantedto produce several seedlings in each pot. Approximately 7 to 10 daysafter seeding, the velvetleaf seedlings were thinned out leaving 2 to 3healthy seedlings per pot.

After the pots were seeded, the pots were moved into the greenhouse, ora growth chamber, and placed on trays with each tray holding 40 to 60pots. The trays were lined with absorbent mats for subirrigation. Thegreenhouse temperature was maintained at 86° F. during the day and 70°F. during the night while the growth chamber was maintained at 15° C.day temperature and 9° C. night temperature. Photoperiod in thegreenhouse was maintained at 14 to 16 hours daylength using supplementallighting, and 10 hours in the growth chamber. The seeded pots werewatered via subirrigation as required.

Depending on the weed species used in a given test, the chemicaltreatments were applied within 14 to 60 days after planting. At thattime, the narrowleaf weeds were approximately 4 to 16 inches tall whilethe broadleaf weeds were 1 to 4 inches tall.

Chemical treatments were applied post-emergence with the foliage of theweeds as the locus of application using a tract sprayer equipped with asingle 8001E spray nozzle. The sprayer was previously calibrated todeliver a spray volume equivalent to about 20 gallons per acre of spraysolution at a spraying pressure of about 30 psi.

The chemical compositions illustrative of compositions of this inventionused in the tests were formulated as tank mixtures the same day ofapplication. The formulations comprised Roundup® (an agriculturallyacceptable salt of N-phosphonomethylglycine, namely the isopropylaminesalt, and inert adjuvant as a surfactant) a silicone copolymer andwater.

Rates of application based on N-phosphonomethyglycine ranged from about1/8 to about 3 pounds glyphosate acid equivalent per acre. Theingredient ratios employed in the formulations were glyphosate tosilicone of about 1:0.1 to 1:10. Rainfall treatment was applied one hourafter spraying of the compositions using a rain tower calibrated todeliver approximately 1/4 inch of simulated rainfall within a period ofabout 15 minutes.

After application of rainfall, the treated plants were placed on cartsand moved into the greenhouse. After the plants had sufficiently driedout, the pots were returned to the greenhouse (growth chamber) trays andarranged in a randomized complete block experimental design. Eachtreatment contained 3 replications. Control plants and appropriatestandard treatments were provided in each test. A duplicate set ofplants which received the same treatment and which were treated in asimilar manner as the rainfall treated plants were also provided forcomparison under no rain condition.

Observations on the effects of the treatments were taken within 7 to 10days for early burndown effects and again within 21 to 28 days aftertreatment for longer term effects. A rating scale of 0% to 100% was usedin estimating the degree of weed control with 0% having no observableeffect and 100% as complete kill of the weed. The degree of burn,chlorosis, necrosis, stature reduction, and other observable effects ofthe treatments on plant species present in the test were taken intoconsideration in making the ratings. Ten examples follow whichillustrate compositions and method of use of this invention.

EXAMPLE 1

Response to barnyardgrass (BYGR) and velvetleaf (VELE) to tank mixturescontaining Roundup® and silicones with or without 1/4 inch of simulatedrainfall--final rating.

    __________________________________________________________________________                     Rain Average % Inhibition (25 DAT)*                          Treatment        (inches)                                                                           BYGR    VELE                                            __________________________________________________________________________    Roundup ® + 0.25%                                                                    FLUID A                                                                             0    100 a   100 a                                                            1/4  30  d-g 37  def                                         Roundup ® + 1%                                                                       FLUID A                                                                             0    100 a   100 a                                                            1/4  87  a   60  bcd                                         Roundup ®    0    100 a   100 a                                                            1/4  28  d-h 73  abc                                         Roundup ® + 0.25%                                                                    L-77  0    63  bc  100 a                                                            1/4  10  f-i 100 a                                           Roundup ® + 1%                                                                       L-77  0    77  ab  100 a                                                            1/4  5   hi  100 a                                           Roundup ® + 0.25%                                                                    FLUID J                                                                             0    50  cd  100 a                                                            1/4  12  e-i 100 a                                           Roundup ® + 1%                                                                       FLUID J                                                                             0    20  e-i 100 a                                                            1/4  7   ghi 100 a                                           Roundup ® + 0.25%                                                                    FLUID H                                                                             0    100 a   100 a                                                            1/4  23  e-i 20  fgh                                         Roundup ® +  1%                                                                      FLUID H                                                                             0    100 a   99  a                                                            1/4  33  def 17  fgh                                         Roundup ® + 0.25%                                                                    FLUID I                                                                             0    97  a   100 a                                                            1/4  20  e-i 3   gh                                          Roundup ® + 1%                                                                       FLUID I                                                                             0    100 a   100 a                                                            1/4  10  f-i 33  d-g                                         Roundup ® + 0.25%                                                                    FLUID B                                                                             0    100 a   99  a                                                            1/4  35  de  53  cde                                         Roundup ® + 1%                                                                       FLUID B                                                                             0    100 a   100 a                                                            1/4  15  e-i 28  e-h                                         Untreated Control                                                                              --   0   i   0   h                                           __________________________________________________________________________     Notes:                                                                        Roundup ® was applied at 3/8 lb ae/A (ae = acid equivalent of             glyphosate).                                                                  Additive concentrations shown are based on percent of total spray volume.     All treatments were applied at a spray gallonage equivalent to 20             gallons/A of spray solution.                                                  L77 = Silwet L77, Union Carbide silicone Surfactant.                          Rainfall treatment equivalent to 1/4 inch of rain was applied                 approximately one hour after herbicidal treatment for a period of 15          minutes.                                                                      Values shown are averages of three replications per treatment.                Means followed by different letters within weed species are significantly     different from one another at the 0.05 probability level using Duncan's       Multiple Range Test.                                                          *DAT = Days after treatment                                              

EXAMPLE 2

Effects of silicones as Roundup® additives on rhizome quackgrass.

    ______________________________________                                                         Glyphosate Rate (1/2 lb ae/A)                                                 Average % Inhibition (28 dat)                                                 QUACKGRASS                                                   Treatment          0 Rain        0.25" Rain                                   ______________________________________                                        Roundup ® + 0.25%                                                                      FLUID A   96    ab    60    fgh                                  Roundup ® + 1%                                                                         FLUID A   100   a     82    a-e                                  Roundup ®          95    ab    40    i                                    Roundup ® + 0.25%                                                                      L-77      81    a-e   50    hi                                   Roundup ® + 1%                                                                         L-77      85    a-e   70    d-g                                  Roundup ® + 0.25%                                                                      FLUID J   99    ab    55    ghi                                  Roundup ® + 1%                                                                         FLUID J   83    a-e   75    c-f                                  Roundup ® + 0.25%                                                                      FLUID C   91    abc   58    f-i                                  Roundup ® + 1%                                                                         FLUID C   100   a     66    e-h                                  Roundup ® + 0.25%                                                                      FLUID G   98    ab    79    b-e                                  Roundup ® + 1%                                                                         FLUID G   98    ab    71    d-g                                  Roundup ® + 0.25%                                                                      FLUID B   100   a     57    f-i                                  Roundup ® + 1%                                                                         FLUID B   99    ab    60    fgh                                  ______________________________________                                         Values shown are averages of three replications per treatment.           

EXAMPLE 3

Response of barnyardgrass to tank mixtures containing Roundup® andsilicone in the absence or presence of 1/4 inch simulated rainfallapplied one hour after treatment. Data show average percent growthinhibition 25 days after treatment. Roundup® was applied at 3/8 lb ae/A;silicones at 0.25% (v/v). The spray gallonage was equivalent to 20gallons per acre of spray solution.

    ______________________________________                                                       Average % Inhibition (25 DAT)                                  Treatment        0 Rain          0.25" Rain                                   ______________________________________                                        Roundup ® + FLUID A                                                                        100     a       30   de                                      Roundup ®    95      a       12   fgh                                     Roundup ® + FLUID D                                                                        20      ef      0    h                                       Roundup ® + FLUID E                                                                        40      d       0    oh                                      Roundup ® + FLUID F                                                                        40      d       2    gh                                      Roundup ® + FLUID C                                                                        100     a       3    gh                                      Roundup ® + FLUID B                                                                        100     a       5    fgh                                     ______________________________________                                    

EXAMPLE 4

Response of barnyardgrass to tank mixtures containing Roundup® andsilicone in the absence or presence of 1/4 inch simulated rainfallapplied one hour after treatment. Data show average percent growthinhibition 24 days after treatment.

    ______________________________________                                                               Average %                                                             Rain    Inhibition (24 DAT)                                    Treatment        (inches)  3/8 lb ae/A                                                                            1/2 lb ae/A                               ______________________________________                                        Roundup ® + 1% FLUID A                                                                     0         100 a    100 a                                                      1/4        27 g-m   63 b-f                                   Roundup ®    0         100 a    100 a                                                      1/4        18 i-m   23 g-m                                   Roundup ® + 1% FLUID J                                                                     0          20 h-m   33 f-l                                                    1/4        23 g-m   50 c-h                                   ______________________________________                                         Note:                                                                         Silicone concentrations are expressed as % of total spray volume based on     a spray gallonage equivalent to 20 gallons/A.                                 Means followed by differenc letters are significantly different from one      another at the 5% probability level based on Duncan's Multiple Range Test                                                                              

EXAMPLE 5

Response of rhizome johnsongrass to tank mixtures containing Roundup®and silicone in the absence or presence of 1/4 inch simulated rainfallapplied one hour after treatment. Data show average percent growthinhibition 23 days after treatment.

    ______________________________________                                                       Average % Inhibition (23 DAT)                                                   Rain                                                         Treatment        (inches)  3/8 lb ae/A                                                                            1/2 lb ea/A                               ______________________________________                                        Roundup ® + 1% FLUID A                                                                     0         99     a   100  a                                                   1/4       76     ab  87   ab                                 Roundup ®    0         53     cd  8    c                                                   1/4       91     ab  40   d                                  Roundup ® + 1% L-77                                                                        0         89     ab  99   a                                                   1/4       99     a   100  a                                  Roundup ®+ 1% FLUID J                                                                      0         100    a   100  a                                                   1/4       100    a   100  a                                  ______________________________________                                         Note:                                                                         Silicone concentrations are expressed as % of the total spray volume base     on a spray gallonage equivalent to 20 gallons/A.                              Means followed by different letters are significantly different from one      another at the 5% probability level based on Duncan's Multiple Range Test                                                                              

EXAMPLE 6

Response of rhizome johnsongrass to tank mixtures containing Roundup®and silicone in the absence or presence of 1/4 inch simulated rainfallapplied one hour after treatment. Data show average percent growthinhibition 28 days after treatment. Roundup® was applied at 3/8 lb ae/A.The spray gallonage was equivalent to 20 gallons per acre of spraysolution.

    ______________________________________                                                                Average %                                             Silicone  Silicone Conc.                                                                              Inhibition (28 DAT)                                   Additive  (%)           0 Rain   0.25" Rain                                   ______________________________________                                        FLUID A   0.0625        93    a    0    e                                               0.125         84    ab   0    e                                               0.25          82    ab   3    e                                               0.5           93    a    2    e                                               1             98    a    0    e                                     NONE      --            15    e    0    e                                     FLUID J   0.0625        3     e    0    e                                               0.125         13    e    0    e                                               0.25          45    d    5    e                                               0.5           96    a    53   cd                                              1             92    a    70   bc                                    FLUID K   0.0625        3     e    0    e                                               0.125         0     e    0    e                                               0.25          10    e    0    e                                               0.5           2     e    2    e                                               1             2     e    2    e                                     FLUID E   0.0625        13    e    0    e                                               0.125         12    e    0    e                                               0.25          0     e    0    e                                               0.5           13    e    0    e                                               1             5     e    3    e                                     ______________________________________                                         Note:                                                                         Silicone concentrations are expressed as % of the total spray volume base     on a spray gallonage equivalent to 20 gallons/A.                         

EXAMPLE 7

Response of rhizome johnsongrass to tank mixtures containing Roundup®and silicone in the absence or presence of 1/4 inch simulated rainfallapplied one hour after treatment. Roundup® was applied at 1/2 lb ae/Aand silicones at 0.5% (v/v). The spray gallonage was equivalent to 20gallons per acre of spray solution.

    ______________________________________                                        Silicone        Average % Inhibition (22 DAT)                                 Additive        0 Rain      0.25" Rain                                        ______________________________________                                        FLUID A         90 a-d      73 a-g                                            NONE            95 ab       27 ijk                                            FLUID J         52 f-i      68 c-h                                            FLUID E         13 kl        5 kl                                             FLUID F         18 kl        7 kl                                             FLUID B         92 a-d      60 e-h                                            ______________________________________                                    

EXAMPLE 8

Effect of Roundup® rate and silicone content on rhizome quackgrasswithout rain and 28 days after treatment. Roundup® rates of 1/4 and 3/8lb ae/A were based on N-phosphonomethylglycine content.

    ______________________________________                                                           Average %                                                                     Inhibition (28 DAT)                                                           1/4 lb ae/A                                                                           3/8 lb ae/A                                        ______________________________________                                        Roundup ® + 0.0625%                                                                     FLUID A    77 e-h    88 a-e                                     Roundup ® + 0.125%                                                                      "          93 ab     91 abc                                     Roundup ® + 0.25%                                                                       "          89 a-e    91 abc                                     Roundup ® + 0.50%                                                                       "          88 a-e    89 a-e                                     Roundup ® + 1%                                                                          "          90 a-d    91 abc                                     Roundup ®            71 gh     83 a-f                                     Roundup ® + 0.0625%                                                                     FLUID B    79 d-h    89 a-d                                     Roundup ® + 0.125%                                                                      "          88 a-e    87 a-e                                     Roundup ® + 0.25%                                                                       "          85 a-f    95 a                                       Roundup ® + 0.50%                                                                       "          92 abc    89 a-e                                     Roundup ® + 1%                                                                          "          93 ab     85 a-f                                     Roundup ® + 0.0625%                                                                     FLUID C    69 h      84 a-f                                     Roundup ® + 0.125%                                                                      "          77 e-h    92 abc                                     Roundup ® + 0.25%                                                                       "          82 b-g    91 abc                                     Roundup ® + 0.50%                                                                       "          85 a-f    89 a-d                                     Roundup ® + 1%                                                                          "          82 b-g    87 a-e                                     Roundup ® + 0.0625%                                                                     FLUID J    58 i      81 c-g                                     Roundup ® + 0.125%                                                                      "          49 ij     82 b-g                                     Roundup ® + 0.25%                                                                       "          41 j      75 fgh                                     Roundup ® + 0.50%                                                                       "          47 j      58 i                                       Roundup ® + 1%                                                                          "          68 h      75 fgh                                     ______________________________________                                    

EXAMPLE 9

Response of rhizome quackgrass to tank mixtures containing Roundup® andsilicone in the absence or presence of 1/4 inch simulated rainfallapplied one hour after treatment. Data show average percent growthinhibition 28 days after treatment. Roundup® was applied at 1/2 lb ae/A.

    ______________________________________                                                           Average %                                                                     Inhibition (28 DAT)                                        Treatment            0 Rain   0.25" Rain                                      ______________________________________                                        Roundup ® + 0.10% FLUID A                                                                      100    a     95   abc                                    Roundup ® + 0.25% FLUID A                                                                      98     ab    87   cd                                     Roundup ® + 1.00% FLUID A                                                                      99     ab    94   abc                                    Roundup ®        99     ab    70   e                                      Roundup ® + 0.10% L-77                                                                         100    a     91   abc                                    Roundup ® + 0.25% L-77                                                                         98     ab    96   abc                                    Roundup ® + 1.00% L-77                                                                         100    a     96   abc                                    Roundup ® + 0.10% FLUID I                                                                      99     ab    79   d                                      Roundup ® + 0.25% FLUID I                                                                      99     ab    93   abc                                    Roundup ® + 1.00% FLUID I                                                                      99     ab    88   bc                                     ______________________________________                                         Note:                                                                         Silicone concentrations are expressed as % of the total spray volume base     on a spray gallonage equivalent to 20 gallons/A.                              Means followed by different letters are significantly different from one      another at the 5% probability level based on Duncan's Multiple Range Test                                                                              

EXAMPLE 10

Response of rhizome quackgrass to tank mixtures containing Roundup® andsilicone without rainfall treatment. Data show average percent growthinhibition 28 days after treatment.

    ______________________________________                                                               Average %                                                                     Inhibition                                                                    (28 DAT)                                                                        1/4 lb  3/8 lb                                       Treatment                ae/A    ae/A                                         ______________________________________                                        Roundup ® + 0.0625%                                                                     FLUID A        75 c-j  80 a-f                                   Roundup ® + 0.125%                                                                      "              75 c-j  95 a                                     Roundup ® + 0.25%                                                                       "              74 d-j  89 a-d                                   Roundup ® + 0.5%                                                                        "              79 a-g  95 a                                     Roundup ® + 1%                                                                          "              89 a-d  93 ab                                    Roundup ®                59 hij  73 d-j                                   Roundup ® + 0.0625%                                                                     FLUID B        78 a-h  71 e-k                                   Roundup ® + 0.125%                                                                      "              68 e-k  92 abc                                   Roundup ® + 0.25%                                                                       "              83 a-e  90 a-d                                   Roundup ® + 0.5%                                                                        "              78 a-h  89 a-d                                   Roundup ® + 1%                                                                          "              82 a-e  89 a-d                                   Roundup ® + 0.0625%                                                                     FLUID C        59 hij  75 c-j                                   Roundup ® + 0.125%                                                                      "              75 c-j  76 b-i                                   Roundup  ® + 0.25%                                                                      "              88 a-d  80 a-f                                   Roundup ® + 0.5%                                                                        "              79 a-g  78 a-h                                   Roundup ® + 1%                                                                          "              74 d-j  83 a-e                                   Roundup ® + 0.0625%                                                                     FLUID J        68 e-k  73 d-j                                   Roundup ® + 0.125%                                                                      "              62 g-k  73 d-j                                   Roundup ® + 0.25%                                                                       "              54 k    61 h-k                                   Roundup ® + 0.5%                                                                        "              58 jk   67 e-k                                   Roundup ® + 1%                                                                          "              68 e-k  73 d-j                                   Roundup ® + 0.125%                                                                      Roundup surfactant                                                                           64 f-k  75 c-j                                   Roundup ® + 0.5%                                                                        Roundup surfactant                                                                           73 d-j  80 a-f                                   ______________________________________                                         Note:                                                                         Additive concentrations are expressed as % of the total spray volume base     on a spray gallonage equivalent to 20 gallons/A.                              Means followed by different letters are significantly different from one      another at the 5% probability level based on Duncan's Multiple Range Test                                                                              

EXAMPLE 11-42

The adjuvant terpolymers shown in Table 2, and having the averagestructure ##STR9## wherein A is a normal alkyl radical having 6 to 24carbon atoms, were prepared according to the above described methods.These terpolymer adjuvants were mixed at a 0.5% level with BEACONherbicide (Ciba-Geigy Agricultural Division) and applied to plants asdescribed infra.

Test Protocol

Individually potted Johnsongrass plants were grown from seeds understandard greenhouse conditions in BACCTO professional potting soil mix.Temperature was controlled at 75+/-2° F. Irradiation consisted of normalsunlight supplemented by high-pressure sodium vapor lamps to provide anadded 1,200 μE/m².s at bench level (μE=microeinstein), wherein theday/night cycle was set at 18 hours and 6 hours, respectively.

Fourteen days after planting, when the plants were at the three-leafstage, they were sprayed with water dispersions of the herbicidecompositions so as to broadcast herbicide (i.e., BEACON) at a rate of0.5 grams (active ingredient) per acre (0.5 g ai/A) along with theadjuvant (i.e., above described terpolymer) at a rate of 1 pint/A.Spraying was accomplished by means of a link-belt sprayer fitted with aTEEJET 8001 E nozzle which delivered the equivalent of 25 gallons/acreof the herbicide dispersion. The BEACON application rate employed waspreviously found to induce approximately 50% injury to the Jonsongrassafter 14 days when a commercial adjuvant, ORTHO X-77 spreader (ChevronChemical Co., San Francisco, Calif.), was mixed with the BEACON andbroadcast at the above rates.

In addition, the rainfastness of the herbicide compositions wasevaluated by spraying half the plants with water in order to simulaterainfall. This procedure consisted of spraying plants from above (8-10inches above plant tops) using a TEEJET nozzle which delivered 0.4gallons of water per minute. This nozzle was also mounted on a chaindrive and reciprocally moved over four plants at a time, each suchtraverse taking about 9-10 seconds. The water spray was started 30minutes after application of the herbicide compositions and wascontinued for approximately 7 minutes, at which point the equivalent ofone inch of "rain" had fallen on each plant.

Plant injury was visually determined using a double-blind experimentalmode wherein four replicates were run for each herbicide composition.Phytotoxicity was ranked from zero, corresponding to no observableeffect, to 100%, corresponding to total destruction of the plant. Theseresults were averaged and the values reported using the above mentionedDuncan's multiple range test to distinguish statistical differences atthe 95% confidence level.

The above described herbicide dispersions were used to spray plants andthe degree of injury, both with and without rain simulation, wasobserved 14 days after spraying with the herbicide dispersions. Theseresults, along with the Duncan statistical annotations, are presented inTable 2. For additional comparison, results from spraying withBEACON+ORTHO X-77, BEACON alone (i.e., without adjuvant) and fromcontrols which were not sprayed with herbicide, are also reported inTable 2.

                                      TABLE 2                                     __________________________________________________________________________           Silicone-Glycol-Silicone Alkane Terpolymer                                         No. of carbons in Percent Injury to Plant                                x y  Alkyl Radical A                                                                        z  m  HLB                                                                              No Rain                                                                             With Rain                                 __________________________________________________________________________    Example                                                                       11     0 0.10                                                                             24       1.90                                                                             12 14.41                                                                            99.sup.a                                                                            45.sup.c                                  12     0 0.10                                                                             12       1.90                                                                             12 14.57                                                                            96.sup.a                                                                            23.sup.d-i                                13     0 1.14                                                                              8       0.86                                                                             24 13.49                                                                            96.sup.a                                                                            23.sup.d-i                                14     0 0.40                                                                             12       1.60                                                                             12 13.52                                                                            95.sup.a                                                                            33.sup.cde                                15     0 1.00                                                                              8       1.00                                                                             32 15.28                                                                            94.sup.a                                                                            13.sup.g-j                                16     0 0.10                                                                              8       1.90                                                                             12 14.62                                                                            94.sup.a                                                                            25.sup.d-h                                17     0 1.25                                                                             12       0.75                                                                             32 13.43                                                                            94.sup.a                                                                            13.sup.g-j                                18     0 0.53                                                                             12       1.47                                                                             32 16.50                                                                            91.sup.a                                                                            13.sup.g-j                                19     0 0.10                                                                             12       1.90                                                                             24 16.75                                                                            90.sup.a                                                                            13.sup.g-j                                20     0 0.14                                                                             24       1.86                                                                             24 16.51                                                                            90.sup.a                                                                            10.sup.hij                                21     0 0.64                                                                             12       1.35                                                                             24 15.24                                                                            90.sup.a                                                                            15.sup.f-j                                22     0 0.64                                                                             12       1.36                                                                             24 15.25                                                                            89.sup.a                                                                            15.sup.f-j                                23     0 0.14                                                                             24       1.86                                                                             24 16.51                                                                            88.sup.a                                                                            15.sup.f-j                                24     0 0.65                                                                             12       1.35                                                                             24 15.22                                                                            88.sup.a                                                                            10.sup.hij                                25     0 0.51                                                                              6       1.49                                                                             12 13.51                                                                            88.sup.a                                                                            18.sup.e-i                                26     0 1.20                                                                              6       0.80                                                                             24 13.43                                                                            88.sup.a                                                                            10.sup.hij                                27     0 0.53                                                                             12       1.47                                                                             32 16.50                                                                            86.sup.a                                                                            10.sup.hij                                28     0 0.70                                                                             24       1.30                                                                             32 15.24                                                                            85.sup.a                                                                            15.sup.f-j                                29     0 1.14                                                                              8       0.86                                                                             24 13.49                                                                            85.sup.a                                                                            23.sup.d-i                                30     0 0.25                                                                              8       1.75                                                                             24 16.50                                                                            84.sup.a                                                                            23.sup.d-i                                31     0 0.30                                                                              6       1.70                                                                             24 16.45                                                                            70.sup.b                                                                            15.sup.f-j                                32     0 1.05                                                                              6       0.95                                                                             32 15.28                                                                            70.sup.b                                                                            10.sup.hij                                33     0 0.10                                                                              6       1.90                                                                             12 14.65                                                                            70.sup.b                                                                            38.sup.cd                                 Comparative                                                                   Examples                                                                      34     2 1.50                                                                             12       2.50                                                                             24 14.89                                                                            38.sup.cd                                                                           15.sup.f-j                                35     0 1.55                                                                              8       0.45                                                                             50 13.56                                                                            38.sup.cd                                                                           25.sup.d-h                                36     0 1.65                                                                              8       0.35                                                                             100                                                                              15.25                                                                            35.sup.cd                                                                           25.sup.d-h                                37     0 0.82                                                                             24       1.18                                                                             24 13.52                                                                            30.sup.def                                                                          28.sup.d-g                                38     0 1.40                                                                             24       0.60                                                                             100                                                                              15.45                                                                            28.sup.d-g                                                                          28.sup.d-g                                39     0 0.65                                                                              6       1.35                                                                             32 16.51                                                                            25.sup.d-h                                                                          18.sup.e-i                                40     0 1.40                                                                             12       0.60                                                                             97 16.50                                                                            25.sup.d-h                                                                          15.sup.f-j                                41     0 1.30                                                                             24       0.70                                                                             50 13.50                                                                            25.sup.d-h                                                                          23.sup.d-i                                42     0 1.70                                                                             12       0.30                                                                             100                                                                              13.92                                                                            18.sup.e-i                                                                          15.sup.f-j                                BEACON + ORTHO X-77           63.sup.b                                                                            13.sup.g-j                                BEACON alone (No Adjuvant)    8.sup.ij                                                                            0.sup.j                                   CONTROL (No Herbicide)        0.sup.j                                                                             0.sup.j                                   __________________________________________________________________________

We claim:
 1. A composition comprising:(I) a Primisulfuron herbicide; and(II) from about 0.1 to about 10 parts by weight, for each part by weightof said herbicide (I), of a silicone glycol-silicone alkane terpolymeradjuvant having the average formula selected from the group consistingof ##STR10## wherein Me denotes a methyl radical, A is a linear orbranched alkyl radical having 6 to 24 carbon atoms, G is a glycol moietyhaving the formula --R'(OCH₂ CH₂)_(m) OZ, in which R' is a divalentalkylene group having 2 to 6 carbon atoms, Z is selected from the groupconsisting of hydrogen, an alkyl radical having 1 to 3 carbon atoms andan acyl group having 2 to 4 carbon atoms and m is 12 to 32, x is 0.01 to3, y is 0.1 to 1.25 and z is 0.75 to 1.9, with the proviso that when theweight fraction of --OCH₂ CH₂ -- groups of said terpolymer (II) is lessthan 0.7 said alkyl radical A contains from 6 to 12 carbon atoms andwhen the weight fraction of --OCH₂ CH₂ -- groups of said terpolymer (II)is more than 0.8 said alkyl radical A contains from 8 to 24 carbonatoms.
 2. The composition according to claim 1, wherein said terpolymerhas the average structure ##STR11## in which Me denotes a methylradical, A is a linear or branched alkyl radical having 6 to 24 carbonatoms, m is 12 to 32, y is 0.1 to 1.25 and z is 0.75 to 1.9, with theproviso that when the weight fraction of --OCH₂ CH₂ -- groups is lessthan 0.7 said alkyl radical A contains from 6 to 12 carbon atoms andwhen the weight fraction of --OCH₂ CH₂ -- groups is more than 0.8 saidalkyl radical A contains from 8 to 24 carbon atoms.
 3. The compositionof claim 2, wherein from 0.5 to 4 parts by weight of said siliconeglycol-silicone alkane terpolymer adjuvant (II) is employed for eachpart by weight of said herbicide (I).
 4. The composition according toclaim 2, wherein said silicone glycol-silicone alkane terpolymeradjuvant (II) has the average formula ##STR12## wherein Me denotes amethyl radical.
 5. In a method for inhibiting the growth of a weedcomprising contacting at least part of the weed with a herbicidalformulation, the improvement comprising using as said herbicidalformulation a composition comprising:(I) a Primisulfuron herbicide; and(II) a silicone glycol-silicone alkane terpolymer adjuvant having theaverage formula selected from the group consisting of ##STR13## whereinMe denotes a methyl radical, A is a linear or branched alkyl radicalhaving 6 to 24 carbon atoms, G is a glycol moiety having the formula--R'(OCH₂ CH₂)_(m) OZ, in which R' is a divalent alkylene group having 2to 6 carbon atoms, Z is selected from the group consisting of hydrogen,an alkyl radical having 1 to 3 carbon atoms and an acyl group having 2to 4 carbon atoms and m is 12 to 32, x is 0.01 to 3, y is 0.1 to 1.25and z is 0.75 to 1.9, with the proviso that when the weight fraction of--OCH₂ CH₂ -- groups of said terpolymer (II) is less than 0.7 said alkylradical A contains from 6 to 12 carbon atoms and when the weightfraction of --OCH₂ CH₂ -- groups of said terpolymer (II) is more than0.8 said alkyl radical A contains from 8 to 24 carbon atoms.
 6. Themethod according to claim 5, wherein said terpolymer has the averagestructure ##STR14## in which Me denotes a methyl radical, A is a linearor branched alkyl radical having 6 to 24 carbon atoms, m is 12 to 32, yis 0.1 to 1.25 and z is 0.75 to 1.9, with the proviso that when theweight fraction of --OCH₂ CH₂ -- groups is less than 0.7 said alkylradical A contains from 6 to 12 carbon atoms and when the weightfraction of --OCH₂ CH₂ -- groups is more than 0.8 said alkyl radical Acontains from 8 to 24 carbon atoms.
 7. The method according to claim 6,wherein said silicone glycol-silicone alkane terpolymer adjuvant (II)has the average formula ##STR15## wherein Me denotes a methyl radical.8. The method according to claim 5, wherein said weed is selected fromthe group consisting of Barnyardgrass, Quackgrass and Johnsongrass. 9.The method according to claim 6, wherein said weed is selected from thegroup consisting of Barnyardgrass, Quackgrass and Johnsongrass.
 10. Themethod according to claim 7, wherein said weed is selected from thegroup consisting of Barnyardgrass, Quackgrass and Johnsongrass.